In this Dec. 30, 2012, photo, Green Bay wide receiver Greg Jennings (85) gains yardage against the Minnesota Vikings during the second half of a game in Minneapolis.

Albert Haynesworth, leading man.

Albert Haynesworth, villain.

The former NFL defensive tackle earns both roles in an evaluation of free agency over the last five years. He was involved in the best decision made by the Tennessee Titans, and the worst for the Washington Redskins.

A two-time All-Pro, Haynesworth became a free agent in 2009. The Titans bowed out rather than destroy their salary structure, a move that became brilliant when Haynesworth flopped in DC.

And did he ever flop, the worst of all the dubious free agent signings during Dan Snyder’s tenure as owner.

Haynesworth was guaranteed a then-record $41 million in a seven-year, $100 million contract signed in the early hours of free agency. On the same day, he infamously declared: “You’re not going to remember Albert Haynesworth as a bust.”

He played only two seasons in Washington, the second one entirely as a backup after he needed several attempts to pass a training camp conditioning test. Haynesworth was traded to New England for a fifth-round draft pick in 2011 and played only one more season in the league.

Haynesworth is a prime example of how dangerous a game free agency can be. In just the past five years, Philadelphia went bust with Nnamdi Asomugha. So did New Orleans with Olin Kreutz. And Buffalo with Vince Young.

All former Pro Bowlers.

Peyton Manning cost Indianapolis a $26 million payday and he never suited up for the Colts again after collecting the money.

Of course, when he got back on the field with Denver, he was the Manning of old, not an old Manning.

At least Asomugha still has a chance to redeem himself — and the Eagles for giving him a five-year, $60 million contract, $24 million guaranteed.

As Eagles owner Jeffrey Lurie has said:

“You notice it with any organization that has had a lot of success, that you will start to reach thinking, ‘That’s the player, that’s the method, that’s the mechanism, that’s the coach, that’s the thing that is going to put us over the top.’”

Sometimes, they find the right guy, such as fullback Vonta Leach for Baltimore in 2011. The All-Pro was a significant contributor to the Ravens’ Super Bowl championship last season.

Michael Turner (2008) was a key to five straight winning seasons in Atlanta, had three seasons with at least 1,300 yards rushing, and scored at least 10 TDs in all five of his years as a Falcon before being released last week.

Julius Peppers signed a six-year, $91.5 million contract before the 2010 season. He’s been an anchor on one of the league’s top defenses, made three straight Pro Bowls and helped the Bears reach the NFC title game in his first year in Chicago.

An even better performer in that span has been San Francisco’s Justin Smith, who plays both defensive end and tackle — and makes a huge impact in both places. Smith helped the 49ers to the conference championship game in 2011 and to the Super Bowl last season.

Smith’s never-back-down style plows the way for linebackers Aldon Smith, Patrick Willis and NaVorro Bowman, each of them an All-Pro, to make plays and hassle the quarterback. The 33-year-old Smith was signed to a six-year contract before the 2008 season after playing his first seven years in the NFL with the Bengals. During last season’s run to the Super Bowl, Smith returned to play with a partially torn left triceps muscle that later required surgery. He has said he typically chips his teeth once a season.

Sometimes, an attitude change is precisely why a free agent is pursued and signed. St. Louis brought in feisty cornerback Cortland Finnegan last year, and he improved the locker room environment. Tennessee needed some veteran savvy at quarterback in 2011 and opted for Matt Hasselbeck, who had taken Seattle to a Super Bowl. The Titans went 9-7 in `11 and now Hasselbeck serves as a backup and mentor for Jake Locker.

The need for a change in attitude also can be why a player is sent packing, particularly after a team heavily invested in him.

Running back Brandon Jacobs barely made it to the end of his only regular season in San Francisco, where he was a nonfactor, and was cut even before the Niners won the conference title.

Enigmatic wide receiver Javon Walker was a disappointment from the start after signing a $55 million, six-year contract in Oakland in the 2008 offseason after being released by Denver. Walker arrived at training camp out of shape, was seriously injured during a robbery in Las Vegas, and then contemplated retirement. In two seasons in Oakland, Walker had 15 catches for 196 yards and one TD, while being paid $14 million.

Tackle Jared Gaither had earned the nickname “Big Lazy” early in his career, and after he signed a four-year, $24.5 million contract with San Diego in 2012, the 6-foot-9, 340-pound Gaither came up with a mysterious back injury in training camp last summer. His work ethic was questioned when he was slow to return. He played in only four of the first 10 games before going on injured reserve.

He’s still there, but for how long?

In the last two years, the NFL has seen an odd free agency dynamic play out with one of its all-time greats: Manning. The four-time MVP has become emblematic of all that works and all that fails with free agency.

The Colts lost the gamble in 2011 that Manning would recover from multiple offseason neck surgeries to lead them back to the playoffs. Instead, Manning never played another down for them, still pocketing more than $26 million as Indianapolis fell to 2-14.

So Indy made the agonizing decision last year to void a $28 million bonus to the still-recovering quarterback.

In leaped several teams, with Denver winning the Manning sweepstakes for $96 million over five years. At 36, Manning was voted Comeback Player of the Year, nearly won another MVP and led the Broncos to an AFC-best 13-3 record.

All of which caused Broncos coach John Fox to say at the NFL scouting combine, “I think he’ll just get stronger and better.”

That’s the approach teams take into free agency, expecting to get stronger and better. It doesn’t always work out, but when they hit, teams don’t think twice about how much they spent.

And when they get it wrong, the damage can be long-lasting.

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AP Pro Football Writer Rob Maaddi in Philadelphia and Sports Writers Janie McCauley in San Francisco and Joseph White in Washington contributed to this story.